datsun.dave

Hey 71Dimer - Those look great. I have a line on a pair of them for my 510 4 door. Was there a lot of fabrication involved to get them mounted?

Thanks a lot for the help guys - if nothing else, I ended up exploring a little more and finally jiggled the right wire. I did go through and clean up all the connections on the fuse box and will work my way through the rest of the car... I will check over on the Realm for the diagram. Just signed up there too... Still curious when the cutoff between 72 and 73 is... and what the differences are...

Anybody have a wiring diagram for a 73 specifically? Anyone know the production change over or the serial numbers by year? I will check the search function...

Almost like rocket surgery... I now have a photobucket account. Top wire is black/blue. Relay was free from fender for this pic to show the wires... I had also opened up the relay and the cover was loose.

Sorry guys - I missed the conversation going on while I was running back and forth to the garage to figure out the wiring diagram... I took some pics that I am just trying to post so you can see my start relay... Production date is 6/72... could be an early 73?? Is there an easy way to ad pics? It took me half an hour to make the one for my profile pic small enough...

Thanks Crash for breaking it down - it helps to have that interpretation for sure. So - this is what I started to write... "As far as I can figure out, power has to come on black blue when key is in start position. That is where we breakdown. Black yellow isn't constant, it only powers up when the key is turned to start. The relay has power on black yellow with the key turned, but no power on black blue..." Then I went out to the car, wiggled all the leads and checked continuity from the black/blue on the ballast resistor back to the harness at the fire wall where I exposed the two black/blue that come up off of the inhibitor switch - confusing, I know - because the inhibitor switch doesn't have black/blue. oh wait. yes it does. And, I wiggled and cleaned up a couple contacts at the fuse box. My inhibitor switch has 2 black/blue coming up into the firewall harness, one of which doubles back to the ignition and one of which makes it's way to the starter relay... and my starter relay has 6 wires. 2 black/yellow, 1 black/blue, 1 black (confirmed as ground) and 2 blue/green (which I have no idea WTF they do...) And yes, my inhibitor switch has 4 wires - two black blue, and two red black (at least that makes sense.) So, after tracing everything I could out on the wiring diagram, I went out to the car to test what happened to the two black/blue at the firewall when I shifted from park to drive. Resistance went from .6 ohm to 65 ohm suggesting that the switch was doing something. Then I accidentally turned the key and started the car. And, the signal lights work, the seatbelt buzzer works, the three gauge caution lights lit up, and everything is normal. I went back and forth in and out of gear, turned the car on and off a couple of times. And everything works. Soooooo, clearly, I have no idea what the problem was, because I conducted pretty much all the same tests previously... I guess I chalk it up to a sticky inhibitor switch or a goofy connection at the fusebox... W. T. F. Upside is, I have a lot better understanding of how the system works. And, I will carry my little jumper wire in the glove box so if the same symptoms present again, I can at least fake my way home...

I don't think there is a problem with the ballast resistor... but the black/blue wire seems to run into the starter relay from the ballast resistor and would appear to be responsible for powering the coil inside the relay. There are two different sources of power to the starter relay performing different functions - black yellow for the starting circuit, and black blue for the relay coil to activate the starting circuit... at least that is how we figured it to work... if this seems like hoakum, please advise... it would not be the first time we failed to interpret something properly... If we take the relay and trip it manually, it completes the circuit and starts the car with the key in the on position, but there is no power at black blue. if we put power to black blue, the relay trips... so it seems that the relay is functioning properly. But there is no power getting to the black blue to trip the relay when the key is in the start position.

We actually opened up the relay. There is power on the black/yellow, but no power on the black/blue that actually trips the relay. The ground is good. We tested that too. I am going to go fiddle with the black/blue circuit from the ballast resistor back to the fuse box and around to the ignition switch and make sure everything looks ok there... any other ideas?

When I tested the switch, we could get continuity both in the park and neutral positions, but not in Drive, Reverse etc... So that seemed to suggest that the switch was doing it's job... but, I don't know what it looks like inside, and I am not sure whether it does anything else - because even though we could get continuity, we couldn't get the power to come back up from the switch to the relay...

Same condition whether in park or neutral. I followed the black/blue around on the wiring diagram and it looks like it could be involved somehow because of where it ducks off to the ignition switch... be nice if some of these things were a little more linear. I can't think about all the other directions some of these circuits can be going at the same time without feeling like I am going to have an aneurism... I will take a good look at the fusebox underneath. There was some corrosion on a couple of terminals there that cleaned up and gave me back some function in the car too. I also still don't have a couple things in the car working - that could be related??? - no signal lights, no radio. But fan, headlights, brakelights, dash lights, horn all work...

And thanks Crash! That is the diagram we are working from. I will check out the black/blue at the fuse box - and I have slapped the shifter silly into every different possible angle and direction to try and get it to do something. Nada.

As I understand it, the black/yellow wires basically loop through the inhibitor switch to create the circuit that powers the starter circuit. By jumping the black/yellow, you take the inhibitor switch out of the circuit, and power the starter circuit directly. Right now, the starter relay itself gets power on one side, but doesn't get power on the blue/black that sparks up the relays coil to actually trip the relay... I was working on this with my friend Jim, who is way smarter than me. We were pretty thorough I think and found the right wiring diagram as there is one floating around that is supposed to be for the automatic, but doesn't show the starter relay. As it stands, the correct diagram has some of the wrong wire colors for my starter relay, which is absolutely original... So, Mike, I am guessing from your question that there should be an audible click at the inhibitor switch when the shifter moves - is this a serviceable part or am I looking for a new one? I would prefer that it work properly, only because the car is so original... I am however incredibly conflicted as this would be a totally different car with twin mikunis, a 5 speed, minilites... sigh. Why did Grandma's always have to drive the automatics. Nevermind. I know.

With ignition in the on position, I hear the linkage moving from park to reverse, but no audible electrical "click". Same with moving from drive to neutral. No audible click to speak of.

Hey Guys - New to Ratsun but long time Roadster and Z owner. Just bought a 72 510 4 door. Hasn't been on the road since 96 after some bodywork on the driver side. Spent a couple of hours trying to diagnose a no start condition. Net result - If I jumper the two black/yellow wires in the starter relay and bypass the automatic transmission inhibitor switch, the car starts effortlessly and runs like a champ. I have checked the wiring, testing for continuity and everything to the inhibitor plugs and from the inhibitor plugs appears to be good. AND I tested the switch function by looking for continuity when the car is in park. I can watch the continuity come and go moving in and out of park, so I think the switch works. The problem seems to be that the power doesn't make it back from the inhibitor switch to the starter relay to power up the coil in the relay - I can't get power on the black/blue wire... Anybody have any ideas what is going on? The car only has 31000 miles, so I am reluctant to yank the automatic, and I don't want to just leave the starter relay bypassed because that just seems bush league... Thanks for the help. dw